isUnified

Usage note: to test if the sequence of tokens is unified (i.e.,
shares a group of features, such as the same gender, number,
grammatical case etc.), you need to test all tokens but the last one
in the following way: call isUnified() for every reading of a token,
and set lastReading to true. For the last token, check the
truth value returned by this method. In previous cases, it may actually be
discarded before the final check. See AbstractPatternRule for
an example.

To make it work in XML rules, the Elements built based on <token>s inside
the unify block have to be processed in a special way: namely the last Element has to be
marked as the last one (by using PatternToken.setLastInUnification()).